def evaluate_score(score):
    """根据分数评估成绩等级"""
    if not isinstance(score, (int, float)):
        return "输入错误：请输入有效的数字"
    
    if score < 0 or score > 100:
        return "输入错误：分数必须在0-100之间"
    elif 90 <= score <= 100:
        return "优秀"
    elif 80 <= score <= 89:
        return "良好"
    elif 70 <= score <= 79:
        return "中等"
    elif 60 <= score <= 69:
        return "合格"
    else:  # 60分以下
        return "不合格"

if __name__ == "__main__":
    try:
        # 获取用户输入的分数
        score_input = input("请输入考试分数（0-100）：")
        score = float(score_input)
        
        # 评估并输出结果
        result = evaluate_score(score)
        print(f"成绩评估：{result}")
    except ValueError:
        print("输入错误：请输入有效的数字")